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We present a novel solver technique for the anisotropic heat flux equation, aimed at the high level of anisotropy seen in magnetic confinement fusion plasmas. Such problems pose two major challenges: (i) discretization accuracy and (ii)…

Numerical Analysis · Mathematics 2024-03-15 Golo A. Wimmer , Ben S. Southworth , Thomas J. Gregory , Xian-Zhu Tang

Heterogeneous anisotropic diffusion problems arise in the various areas of science and engineering including plasma physics, petroleum engineering, and image processing. Standard numerical methods can produce spurious oscillations when they…

Numerical Analysis · Mathematics 2015-05-18 Xianping Li , Weizhang Huang

Nonlinear diffusion equations of spectral transfer are systematically derived for anisotropic magnetohydrodynamics in the regime of wave turbulence. The background of the analysis is the asymptotic Alfv\'en wave turbulence equations from…

Solar and Stellar Astrophysics · Physics 2015-05-19 Sebastien Galtier , Eric Buchlin

A direct numerical solution of the radiative transfer equation or any kinetic equation is typically expensive, since the radiative intensity depends on time, space and direction. An expansion in the direction variables yields an equivalent…

Mathematical Physics · Physics 2023-10-10 Benjamin Seibold , Martin Frank

We show that standard algorithms for anisotropic diffusion based on centered differencing (including the recent symmetric algorithm) do not preserve monotonicity. In the context of anisotropic thermal conduction, this can lead to the…

Astrophysics · Physics 2008-11-26 Prateek Sharma , Gregory W. Hammett

We developed a novel contactless frequency-domain approach to study thermal transport, which is particularly convenient when thermally anisotropic materials are considered. The method is based on a similar line-shaped heater geometry as…

We generalize Einstein's probabilistic method for the Brownian motion to study compressible fluids in porous media. The multi-dimensional case is considered with general probability distribution functions. By relating the expected…

Analysis of PDEs · Mathematics 2025-03-06 Luan Hoang , Akif Ibragimov

The cutoff method, which cuts off the values of a function less than a given number, is studied for the numerical computation of nonnegative solutions of parabolic partial differential equations. A convergence analysis is given for a broad…

Numerical Analysis · Mathematics 2015-06-05 Changna Lu , Weizhang Huang , Erik S. Van Vleck

We present a numerical method for solving the time-independent thermal radiative transfer (TRT) equation or the neutron transport (NT) equation when the opacity or cross-section varies rapidly in energy (frequency). The approach is based on…

Numerical Analysis · Mathematics 2016-12-21 T. S. Haut , C. Ahrens , A. Jonko , R. Lowrie , A. Till

A form of the conservation equations for fluid dynamics is presented, deduced using slightly less restrictive hypothesis than those necessary to obtain the Westervelt equation. This formulation accounts for full wave diffraction,…

Fluid Dynamics · Physics 2015-05-26 Roberto Velasco-Segura , Pablo L. Rendón

We propose a novel formulation for parametric finite element methods to simulate surface diffusion of closed curves, which is also called as the curve diffusion. Several high-order temporal discretizations are proposed based on this new…

Numerical Analysis · Mathematics 2024-08-27 Harald Garcke , Wei Jiang , Chunmei Su , Ganghui Zhang

Astrophysical plasmas are subject to a tight connection between magnetic fields and the diffusion of particles, which leads to an anisotropic transport of energy. Under the fluid assumption, this effect can be reduced to an…

Astrophysics of Galaxies · Physics 2016-01-13 Yohan Dubois , Benoît Commerçon

In this contribution, a wave equation with a time-dependent variable-order fractional damping term and a nonlinear source is considered. Avoiding the circumstances of expressing the nonlinear variable-order fractional wave equations via…

Numerical Analysis · Mathematics 2023-07-17 Karel Van Bockstal , Mahmoud A. Zaky , Ahmed S. Hendy

We introduce numerical methods for simulating the diffusive motion of rigid bodies of arbitrary shape immersed in a viscous fluid. We parameterize the orientation of the bodies using normalized quaternions, which are numerically robust,…

Soft Condensed Matter · Physics 2015-10-28 Steven Delong , Florencio Balboa Usabiaga , Aleksandar Donev

We study the Radiative Transfer equations coupled with the time dependent temperature equation of a fluid: existence, uniqueness, a maximum principle are established. A short numerical section illustrates the pros and cons of the method.

Analysis of PDEs · Mathematics 2021-12-30 Francois Golse , Olivier Pironneau

In this paper, we propose and analyze a new semi-implicit stochastic multiscale method for the radiative heat transfer problem with additive noise fluctuation in composite materials. In the proposed method, the strong nonlinearity term…

Numerical Analysis · Mathematics 2026-05-12 Shan Zhang , Yajun Wang , Xiaofei Guan

This article studies a fully implicit finite volume scheme for transient nonlinear heat transport equations coupled by nonlocal interface conditions modeling diffuse-gray radiation between the surfaces of (both open and closed) cavities.…

Numerical Analysis · Mathematics 2014-07-08 Peter Philip

Explicit numerical finite difference schemes for partial differential equations are well known to be easy to implement but they are particularly problematic for solving equations whose solutions admit shocks, blowups and discontinuities.…

Numerical Analysis · Mathematics 2016-10-19 Christopher. N. Angstmann , Bruce I. Henry , Byron A. Jacobs , Anna V. McGann

For a class of convection-diffusion equations with variable diffusivity, we construct third order accurate discontinuous Galerkin (DG) schemes on both one and two dimensional rectangular meshes. The DG method with an explicit time stepping…

Numerical Analysis · Mathematics 2019-07-30 Hui Yu , Hailiang Liu

This paper considers one-dimensional heat transfer in a media with temperature-dependent thermal conductivity. To model the transient behavior of the system, we solve numerically the one-dimensional unsteady heat conduction equation with…

Numerical Analysis · Mathematics 2018-11-16 Stefan M Filipov , István Faragó